In general, current ITU-T G.8032 protocol specifications and the like do not adequately cover or address ring interconnection scenarios where an interconnection node becomes isolated by multiple faults. For example, in a network including a 100G major ring with subtending 10G and/or 1G sub-rings, multiple faults on the 100G major ring may isolate an interconnection node between the 100G major ring and/or subtending 10G and/or 1G sub-rings, resulting in the permanent disruption of end-to-end client traffic continuity—despite the fact that there is a potentially realizable alternative path through the network.
Thus, what are still needed in the art are protection systems and methods that, in such scenarios, provide a mechanism to identify/determine when an interconnection node has been isolated (i.e. when there is no connectivity between a pair of interconnection nodes), from a data path perspective. Preferably, if/when this condition exists, actions are triggered on the subtending sub-ring that essentially perform a protection switch (which causes the subtending sub-ring nodes to cleanse their forwarding tables), and, more importantly, that remove any channel blocks on the subtending sub-ring.